Substrate provided with a stack having thermal properties comprising at least one layer comprising silicon-zirconium nitride enriched in zirconium, its use and its manufacture

ABSTRACT

A transparent substrate is provided on a main face with a stack of thin layers including a single metallic functional layer having properties of reflection in the infrared region and/or in the solar radiation region, in particular based on silver or on silver-containing metal alloy, and two antireflective coatings. The antireflective coatings each include at least one dielectric layer. The functional layer is positioned between the two antireflective coatings. At least the antireflective coating located between the substrate and the functional layer, indeed even both antireflective coatings, include(s) a layer including silicon-zirconium nitride, SixZryNz, with an atomic ratio of Zr to the sum Si+Zr, y/(x+y), which is between 25.0% and 40.0%, these values being incorporated, indeed even between 27.0% and 37.0%, these values being incorporated.

The invention relates to a transparent substrate in particular made of arigid mineral material, such as glass, said substrate being coated witha stack of thin layers comprising a functional layer of metallic typewhich can influence solar radiation and/or long wavelength infraredradiation.

The invention more particularly relates to the use of such substratesfor manufacturing thermal insulation and/or solar protection glazings.These glazings may be intended to equip both buildings and vehicles, inparticular with a view to reducing the air-conditioning load and/orpreventing excessive overheating (“solar control” glazings) and/orreducing the amount of energy dissipated toward the outside (“low-e”glazings) driven by the ever increasing importance of glazed surfaces inbuildings and vehicle compartments.

These glazings can furthermore be incorporated in glazings havingspecific functionalities, such as, for example, heated glazings orelectrochromic glazings.

One type of stack of layers known for conferring such properties onsubstrates comprises a metallic functional layer having properties ofreflection in the infrared region and/or in the solar radiation region,in particular a metallic functional layer based on silver or on asilver-containing metal alloy.

In this type of stack, the functional layer is thus positioned betweentwo antireflective coatings each generally comprising several layerswhich are each made of a dielectric material of the nitride type, inparticular silicon nitride or aluminum nitride, or of the oxide type.From the optical viewpoint, the aim of these coatings, which frame themetallic functional layer, is to render this metallic functional layer“anti reflective”.

A blocker coating is, however, sometimes inserted between one or eachantireflective coating and the metallic functional layer: a blockercoating positioned under the functional layer in the direction of thesubstrate and/or a blocker coating positioned on the functional layer onthe opposite side from the substrate.

It is known, for example from the European patent application No. EP 718250, that a “wetting” dielectric layer based on zinc oxide positioneddirectly under a silver-based metallic functional layer, in thedirection of the carrying substrate, promotes the achieving of anappropriate crystallographic state of the metallic functional layerwhile exhibiting the advantage of being able to withstand ahigh-temperature bending or tempering heat treatment.

Furthermore, this document discloses the favorable effect of thepresence of a layer deposited in the metallic form directly on and incontact with the silver-based functional layer for the protection of thefunctional layer during the deposition of the other layers on top andduring a high-temperature heat treatment. A person skilled in the artknows this type of layer under the generic term of “blocker layer” or“blocker”.

This document discloses especially that the presence of a barrier layer,for example comprising silicon nitride, in each of the antireflectivecoatings, one below the wetting layer in the direction of the substrateand the other above the blocker layer, makes it possible to produce astack which resists well a bending or tempering heat treatment.

One aim of the invention is to improve the prior art by developing anovel type of stack of layers being mono-functional-layer, whichexhibits a low sheet resistance (and thus a reduced emissivity) but alsoa high luminous transmission and a high solar factor, this being thecase optionally after one (or more) high-temperature bending and/ortempering and/or annealing heat treatment(s).

One aim of the invention is furthermore for the stack to exhibit afavorable colorimetry, this being the case optionally after one (ormore) high-temperature bending and/or tempering and/or annealing heattreatment(s), and in particular a color in reflection on the stack sidewhich is not too red and/or a color in transmission which is not tooyellow.

It has been discovered that, surprisingly, the presence of a layercomprising silicon-zirconium nitride with a certain atomic proportion ofzirconium by the assembly formed by the silicon and the zirconium, insuch a stack, had very favorable effects on the achieving of a highersolar factor, this being the case both in the double glazingconfiguration and in the triple glazing configuration, and on theachieving of such a colorimetry.

A subject-matter of the invention is thus, in its broadest sense, atransparent substrate as claimed in claim 1. The dependent claim'sexhibit advantageous alternative forms.

The transparent substrate is thus provided on a main face with a stackof thin layers comprising a single metallic functional layer havingproperties of reflection in the infrared region and/or in the solarradiation region, in particular based on silver or on asilver-containing metal alloy, and two antireflective coatings, saidantireflective coatings each comprising at least one dielectric layer,said functional layer being positioned between the two antireflectivecoatings. This substrate is noteworthy in that at least theantireflective coating located between said substrate and saidfunctional layer, indeed even both antireflective coatings, comprise(s)a layer comprising silicon-zirconium nitride, Si_(x)Zr_(y)N_(z), with anatomic ratio of Zr to the sum Si+Zr, y/(x+y), which is between 25.0% and40.0%, these values being incorporated.

A particularly appropriate range of atomic ratio of Zr to the sum Si+Zr,y/(x+y), is between 26.32% and 37.5%, these values being incorporated.This material can be deposited with a target comprising from 70.0 atom %to 60.0 atom % of Si per 25.0 atom % to 36.0 atom % of Zr; this targetbeing sputtered in a nitrogen-containing atmosphere.

Another particularly appropriate range of atomic ratio of Zr to the sumSi+Zr, y/(x+y), is between 27.0% and 37.0%, these values beingincorporated.

It is possible for said layer comprising silicon-zirconium nitride,Si_(x)Zr_(y)N_(z), indeed even for each layer comprisingsilicon-zirconium nitride, Si_(x)Zr_(y)N_(z), to comprise an atomicratio of Zr to the sum Si+Zr which is between 26.0% and 30.0%, thesevalues being incorporated, or between 31.0% and 38.0%, these valuesbeing incorporated, or between 25.5% and 32.5%, these values beingincorporated.

The antireflective coating located between said substrate and saidfunctional layer can be the only one of the two antireflective coatingsto comprise a layer comprising silicon-zirconium nitride,Si_(x)Zr_(y)N_(z), and optionally it can comprise a single layercomprising silicon-zirconium nitride, Si_(x)Zr_(y)N_(z), with an atomicratio of Zr to the sum Si+Zr, y/(x+y), which is between 25.0% and 40.0%,these values being incorporated, indeed even between 27.0% and 37.0%,these values being incorporated.

In the case where the stack comprises several layers comprisingsilicon-zirconium nitride, Si_(x)Zr_(y)N_(z), then the atomic ratio ofZr to the sum Si+Zr, y/(x+y), for each of these layers is preferablybetween 25.0% and 40.0%, these values being incorporated, indeed evenfor each of these layers is between 27.0% and 37.0%, these values beingincorporated, but it is not necessarily the same for all these layerscomprising silicon-zirconium nitride, Si_(x)Zr_(y)N_(z).

It is possible for the ratio y/(x+y) to be different for two layerscomprising silicon-zirconium nitride, Si_(x)Zr_(y)N_(z), of said stack.

In the case where each of the two antireflective coatings comprises alayer comprising silicon-zirconium nitride, Si_(x)Zr_(y)N_(z), they canoptionally each comprise a single layer comprising silicon-zirconiumnitride, Si_(x)Zr_(y)N_(z), with an atomic ratio of Zr to the sum Si+Zr,y/(x+y), which is between 25.0% and 40.0%, these values beingincorporated, indeed even between 27.0% and 37.0%, these values beingincorporated, or between 26.0% and 30.0%, these values beingincorporated, or between 31.0% and 38.0%, these values beingincorporated, or between 25.5% and 32.5%, these values beingincorporated.

A particularly appropriate range of atomic ratio of Zr to the sumAl+Si+Zr, y/(w+x+y), is between 25.0% and 36.0%, these values beingincorporated. This material can be deposited with a target comprisingfrom 70.0 atom % to 60.0 atom % of Si per 25.0 atom % to 36.0 atom % ofZr with 5.0 atom % of Al in all cases; this target being sputtered in anitrogen-containing atmosphere.

“Transparent substrate” within the meaning of the present inventionshould be understood as meaning that the substrate is not opaque andthat it would exhibit, without the stack, a luminous transmission of atleast 5%.

“Coating” within the meaning of the present invention should beunderstood as meaning that there may be a single layer or several layersof different materials within the coating.

“In contact” is understood to mean, within the meaning of the invention,that no layer is interposed between the two layers under consideration.

“Based on” is understood to mean, within the meaning of the invention,that the element or the material thus denoted is present at more than 50atom % in the layer under consideration.

Furthermore, in the present document, all the refractive indices areindicated with respect to a wavelength of 550 nm; the opticalthicknesses of the layers are the product of the physical thickness ofthis layer by this refractive index at this wavelength and the opticalthicknesses of the coating are the sum of the optical thicknesses of allthe dielectric layers of the coating; by default, if thephysical/optical distinction is not indicated for a thickness, this is aphysical thickness.

In the present document, the dielectric layers can be differentiatedinto three categories:

-   -   low-index layers, the refractive index of which is n<1.95    -   medium-index layers, the refractive index of which is 1.95        n<2.10    -   high-index layers, the refractive index of which is n>2.10.

Advantageously, the single metallic functional layer having propertiesof reflection in the infrared region and/or in the solar radiationregion is a continuous layer.

Advantageously, the stack according to the invention does not comprise alayer comprising titanium oxide; titanium dioxide, TiO₂, exhibits a veryhigh refractive index and this index may be too high for the targetedapplications. Substoichiometric titanium oxide, TiO_(b) with b which isa number below 2, can constitute a high-index layer but its refractiveindex is a function of its oxidation and its oxidation is difficult tocontrol industrially; the stack according to the invention is thuseasier to manufacture industrially.

Preferably, said layer comprising silicon-zirconium nitride,Si_(x)Zr_(y)N_(z), of the stack according to the invention, or each ofthe layers comprising silicon-zirconium nitride of the stack accordingto the invention, does not comprise titanium.

Preferably, said layer comprising silicon-zirconium nitride,Si_(x)Zr_(y)N_(z), of the stack according to the invention is made ofsilicon-zirconium nitride, Si_(x)Zr_(y)N_(z), or is made ofsilicon-zirconium nitride doped with aluminum, Si_(x)Zr_(y)N_(z):Al.

Preferably, said layer comprising silicon-zirconium nitride,Si_(x)Zr_(y)N_(z), exhibits a nitridation z of between 4/3(x+y) and5/3(x+y), these values being incorporated; preferably again, each layercomprising silicon-zirconium nitride, Si_(x)Zr_(y)N_(z), exhibits anitridation z of between 4/3(x+y) and 5/3(x+y), these values beingincorporated.

Preferably, furthermore, said layer comprising silicon-zirconium nitrideof said stack, or each of the layers comprising silicon-zirconiumnitride of said stack, does not comprise deliberately introduced oxygen.The presence of oxygen in the layer or layers comprisingsilicon-zirconium nitride, Si_(x)Zr_(y)N_(z), is to be avoided as thisresults in a decrease in the refractive index of the layer. The factthat this layer does not comprise oxygen should be understood as meaningthat there is no oxygen in a significant amount with respect to thenitrogen, that is to say in a relative amount of at least 5 atom % withrespect to the total amount of nitrogen and oxygen, it being known thatthe affinity of the elements Si and Zr is greater for oxygen than fornitrogen.

In a specific alternative form, the antireflective coating locatedbetween said substrate and said functional layer additionally comprisesa layer comprising zirconium-free silicon nitride, said layer comprisingzirconium-free silicon nitride preferably being located between saidsubstrate and said layer comprising silicon-zirconium nitride,Si_(x)Zr_(y)N_(z), and more preferably both directly on said main faceof the substrate and directly under said layer comprisingsilicon-zirconium nitride, Si_(x)Zr_(y)N_(z).

Preferably then, said layer of the antireflective coating locatedbetween said substrate and said functional layer and comprisingzirconium-free silicon nitride exhibits a thickness of between 5.0 and25.0 nm, these values being included, indeed even between 15.0 and 20.0nm, these values being included.

In another specific alternative form, which can optionally be combinedwith the preceding one, the antireflective coating located above saidfunctional layer on the opposite side from said substrate additionallycomprises a layer comprising zirconium-free silicon nitride, said layercomprising zirconium-free silicon nitride preferably being located abovesaid layer comprising silicon-zirconium nitride, Si_(x)Zr_(y)N_(z).

Preferably then, said layer of the antireflective coating located abovesaid functional layer and comprising zirconium-free silicon nitrideexhibits a thickness of between 25.0 and 35.0 nm, these values beingincluded.

These solutions make it possible reduce the cost as the zirconium-freesilicon nitride is less expensive than the silicon-zirconium nitride.

In a specific alternative form, the antireflective coating located abovesaid functional layer and on the opposite side from said substrateadditionally comprises a layer made of a dielectric material having alow index, in particular based on silicon oxide. The material of thislayer can consist solely of Si and O; it can in particular be silicondioxide or silicon dioxide doped with aluminum. This layer made of adielectric material having a low index is preferably the finaldielectric layer of the antireflective coating located above saidfunctional layer.

The material of this low-index dielectric layer preferably exhibits anindex of between 1.60 and 1.80; the layer preferably exhibits athickness of between 15.0 and 60.0 nm, indeed even between 20.0 and 58.0nm, indeed even between 30.0 and 55.0 nm.

A layer based on zinc oxide can be located below and in contact withsaid functional layer. This has the effect of actively participating inthe obtaining of a metallic functional layer exhibiting a high degree ofcrystallization and thus a low sheet resistance and thus a lowemissivity.

Preferably, said layer comprising silicon-zirconium nitride,Si_(x)Zr_(y)N_(z), which is located between said substrate and saidfunctional layer, exhibits a thickness of between 10.0 and 30.0 nm,these values being included.

Preferably, furthermore, said layer comprising silicon-zirconiumnitride, Si_(x)Zr_(y)N_(z), which is located above said functional layeron the opposite side from said substrate, exhibits a thickness ofbetween 6.0 and 12.0 nm, these values being included.

Preferably, the stack does not comprise any layer comprisingsilicon-zirconium nitride, Si_(x)Zr_(y)N_(z), which would not be with anatomic ratio of Zr to the sum Si+Zr, y/(x+y), which is between 25.0% and40.0%.

The stack can thus comprise a final layer (overcoat), that is to say aprotective layer. This protective layer preferably exhibits a physicalthickness of between 0.5 and 10.0 nm.

The glazing according to the invention incorporates at least thesubstrate carrying the stack according to the invention, optionally incombination with at least one other substrate. Each substrate can beclear or tinted. One of the substrates at least in particular can bemade of bulk-tinted glass. The choice of coloration type will depend onthe level of luminous transmission and/or on the colorimetric appearancewhich are desired for the glazing once its manufacture has beencompleted.

The glazing according to the invention can exhibit a laminatedstructure, combining in particular at least two rigid substrates of theglass type by means of at least one sheet of thermoplastic polymer, inorder to exhibit a structure of glass/stack of thinlayers/sheet(s)/glass type. The polymer can in particular be based onpolyvinyl butyral PVB, ethylene/vinyl acetate EVA, polyethyleneterephthalate PET or polyvinyl chloride PVC.

The glazing can furthermore exhibit a structure of glass/stack of thinlayers/polymer sheet(s) type.

The glazings according to the invention are capable of being subjectedto a heat treatment without damage to the stack of thin layers. They arethus optionally bent and/or tempered.

The glazing can be bent and/or tempered while consisting of a singlesubstrate, that provided with the stack. It is then a “monolithic”glazing. In the case where they are bent, in particular for the purposeof forming glazings for vehicles, the stack of thin layers is preferablyfound on a face which is at least partially nonplanar.

The glazing can also be a multiple glazing, in particular a doubleglazing, it being possible for at least the substrate carrying the stackto be bent and/or tempered. It is preferable in a multiple glazingconfiguration for the stack to be positioned so as to face the insertedgas-filled cavity. In a laminated structure, the stack can be in contactwith the polymer sheet.

The glazing can also be a triple glazing consisting of three glasssheets separated in pairs by a gas-filled cavity. In a triple glazingstructure, the substrate carrying the stack can be on face 2 and/or onface 5, when it is considered that the incident direction of thesunlight traverses the faces in increasing order of their number.

When the glazing is monolithic or multiple, of the double glazing,triple glazing or laminated glazing type, at least the substratecarrying the stack can be made of bent or tempered glass, it beingpossible for this substrate to be bent or tempered before or after thedeposition of the stack.

The present invention furthermore relates to a process of themanufacture of the substrate according to the invention, in which saidlayer comprising silicon-zirconium nitride, Si_(x)Zr_(y)N_(z), ismanufactured by sputtering, in a nitrogen-comprising atmosphere, atarget comprising an atomic ratio of Zr to the sum Si+Zr, y/(x+y), whichis between 25.0% and 40.0%, these values being incorporated, indeed even26.32% and 37.5%, these values being incorporated, indeed even between27.0% and 37.0%, these values being incorporated.

Preferably, said atmosphere does not comprise oxygen. The fact that thisatmosphere does not comprise oxygen should be understood as meaning thatthere is no oxygen deliberately introduced into the sputteringatmosphere of said target.

The present invention furthermore relates to a target for theimplementation of the process according to the invention, said targetcomprising an atomic ratio of Zr to the sum Si+Zr, y/(x+y), which isbetween 25.0% and 40.0%, these values being incorporated, indeed even26.32% and 37.5%, these values being incorporated, indeed even between27.0% and 37.0%, these values being incorporated.

Advantageously, the present invention thus makes it possible to producea stack of thin layers being mono-metallic-functional-layer whichexhibits a greater solar factor and a satisfactory colorimetricappearance, in particular after bending or temping heat treatment.

The details and advantageous characteristics of the invention emergefrom the following nonlimiting examples, illustrated by means of theappended figures which illustrate:

in FIG. 1, a functional monolayer stack, the functional layer beingdeposited directly under an overblocker coating;

in FIG. 2, a double glazing solution incorporating a functionalmonolayer stack;

in FIG. 3, the curve of refractive index, at 550 nm, ofsilicon-zirconium nitride (“SiZr”) as a function of the content of Zrwith respect to the sum of Zr+Si, and also the refractive index, at 550nm, of titanium dioxide TiO₂; and

in FIG. 4, the curve of the coefficient of absorption, at 380 nm, ofsilicon-zirconium nitride (“SiZr”) as a function of the content of Zrwith respect to the sum of Zr+Si, and also the coefficient ofabsorption, at 380 nm, of titanium dioxide TiO₂.

In FIGS. 1 and 2, the proportions between the thicknesses of thedifferent layers or of the different elements are not respected in orderto make them easier to read.

FIG. 1 illustrates a structure of a mono-functional-layer stack 14according to the invention deposited on a face 29 of a transparent glasssubstrate 30, in which the single functional layer 140, in particularbased on silver or on a silver-containing metal alloy, is positionedbetween two antireflective coatings, the underlying antireflectivecoating 120 located under the functional layer 140 in the direction ofthe substrate 30 and the overlying antireflective coating 160 positionedabove the functional layer 140 on the opposite side from the substrate30.

These two antireflective coatings 120, 160, each comprise at least onedielectric layer 122, 123, 124, 126, 128; 162, 163, 164, 166, 168.

Optionally, on the one hand, the functional layer 140 can be depositeddirectly on an underblocker coating (not illustrated) positioned betweenthe underlying antireflective coating 120 and the functional layer 140and, on the other hand, the functional layer 140 can be depositeddirectly under an overblocker coating 150 positioned between thefunctional layer 140 and the overlying antireflective coating 160.

The underblocker and/or overblocker layers, although deposited inmetallic form and presented as being metallic layers, are sometimes inpractice oxidized layers since one of their functions (in particular forthe overblocker layer) is to become oxidized during the deposition ofthe stack in order to protect the functional layer.

When a stack is used in a multiple glazing 100 of double glazingstructure, as illustrated in FIG. 2, this glazing comprises twosubstrates 10, 30 which are held together by a frame structure 90 andwhich are separated from one another by an inserted gas-filled cavity15.

The glazing thus provides a separation between an external space ES andan internal space IS.

The stack can be positioned on face 3 (on the sheet furthest inside thebuilding when considering the incident direction of the sunlightentering the building and on its face facing the gas-filled cavity).

FIG. 2 illustrates this positioning (the incident direction of thesunlight entering the building being illustrated by the double arrow) onface 3 of a stack of thin layers 14 positioned on an internal face 29 ofthe substrate 30 in contact with the inserted gas-filled cavity 15, theother face 31 of the substrate 30 being in contact with the internalspace IS.

However, it can also be envisaged that, in this double glazingstructure, one of the substrates exhibits a laminated structure.

The layers deposited can be classified into three categories:

i—the layers made of antireflective/dielectric material, exhibiting ann/k ratio over the entire wavelength range of the visible region ofgreater than 5: the layers based on silicon nitride, based onsilicon-zirconium nitride, based on zinc oxide, based on zinc tin oxide,based on titanium oxide, based on titanium-zirconium oxide, based onsilicon oxide, and the like;

ii—the metallic functional layers made of material having properties ofreflection in the infrared region and/or in the solar radiation region:for example based on silver or made of silver: it has been found thatsilver exhibits a ratio 0<n/k<5 over the entire wavelength range of thevisible region, but its electrical resistivity in the bulk state is lessthan 10⁻⁶ Ω·cm;

iii—underblocker and overblocker layers intended to protect thefunctional layer from modification to its nature during the depositionof the stack and/or during a heat treatment; the refractive index ofthese layers is not considered in the optical definition of the stack.

For all the examples below, the names of constituent layer materialsdenote the following materials, with their refractive index, measured at550 nm:

TABLE 2 Name Material Stoichiometry Index SiN Silicon nitride doped withSi₃N₄:Al 2.10 aluminum ZnO Zinc oxide ZnO 2.00 NiCr Nickel-chromiumalloy Ni_(0.8)Cr_(0.2) — SiZrN′ conventional silicon-Si_(x′)Zr_(y′)N_(z′) with 2.12-2.30 zirconium nitride 5.0% ≤ y′/(y′ +x′) < 25.0% SiZrN Silicon-zirconium nitride Si_(x)Zr_(y)N_(z) with2.31-2.60 enriched in Zr 25.0% ≤ y/(y + x) ≤ 40.0% SiZrN″Silicon-zirconium nitride Si_(x″)Zr_(y″)N_(z″) with >2.60  excessivelyriched in Zr y″/(y″ + x″) > 40.0% TiO Titanium oxide TiO_(b) 2.44 TiZrOTitanium-zirconium oxide Ti_(c)Zr_(d)O 2.38 SnZnO Zinc-tin oxideSn_(e)Zn_(f)O 1.95 SiO Silicon dioxide doped with SiO₂:Al 1.55 aluminumAg Ag —

This table shows in particular that silicon-zirconium nitride enrichedin Zr, on the sixth line, is a material, the refractive index of whichis higher than that of silicon nitride doped with aluminum, on thesecond line, and higher than that of conventional silicon nitride dopedwith zirconium, on the fifth line.

The refractive index at 550 nm and also the coefficient of absorption at380 nm, which represents the absorption of the material in the blueregion, of silicon-zirconium nitride as a function of the atomic contentof Zr with respect to the sum Zr+Si are illustrated respectively inFIGS. 3 and 4. It is considered that the doping with aluminum does notinfluence this refractive index and this coefficient of absorption.

These FIGS. 3 and 4 show that silicon-zirconium nitride, the Zr/(Zr+Si)atomic ratio of which is between 25.0% and 40.0%, makes it possible toachieve a high refractive index, while exhibiting a low absorption inthe blue region, in order to avoid an excessively red appearance inreflection and an excessively yellow appearance in transmission.

In this range from 25.0 to 40.0%, the refractive index is close to thatof TiO₂; silicon-zirconium nitride enriched in Zr can thus besubstituted for TiO₂; the coefficient of absorption is admittedly higherthan that of TiO₂ but this increase is relatively low.

In the range between 27.0% and 37.0%, the refractive index is virtuallyidentical to that of TiO₂ and the coefficient of absorption is veryclose to 0.1, which is an acceptable value.

A general configuration of a stack of thin layers, in connection withFIG. 1, is presented in table 3 below, with, for the layers, therecommended materials and also the recommended ranges of thicknesses forthis general configuration.

TABLE 3 Thicknesses Layer No. Coating Material (nm) 168 160 SiN25.0-35.0 166 SiZrN  6.0-12.0 162 ZnO 3.0-8.0 150 NiCr  0-1.0 140 Ag 9.0-16.0 128 120 ZnO 3.0-8.0 126 SiZrN 10.0-30.0 124 SiZrN′   0-15.0122 SiN  5.0-15.0

In this configuration, the two antireflective coatings 120 and 160 eachcomprise a SiZrN layer based on silicon-zirconium nitride enriched inZr.

When the stack comprises at least one SiZrN layer based onsilicon-zirconium nitride enriched in Zr in each of the twoantireflective coatings, in the underlying antireflective coating 120,the layer based on silicon-zirconium nitride enriched in Zr,Si_(x)Zr_(y)N_(z), can be the sole high-index layer; its opticalthickness can then represent between 70.0% (for y/(x+y) close to 25.0%)and 50.0% (for y/(x+y) close to 40.0%) of the optical thickness of theunderlying antireflective coating 120.

However, it is possible for this underlying antireflective coating 120to comprise several high-index layers; in this case, in the underlyingantireflective coating 120, the layer based on silicon-zirconium nitrideenriched in Zr, Si_(x)Zr_(y)N_(z), can then represent between 35.0% (fory/(x+y) close to 25.0%) and 25.5% (for y/(x+y) close to 40.0%) of theoptical thickness of the underlying antireflective coating 120; it thenbeing possible for the optical thickness of the other high-index layer(such as, for example, a layer made of SiZrN′, based on conventionalsilicon-zirconium nitride) or the sum of the optical thicknesses of theother high-index layers, in the case where there are several of them, torespectively represent between 35.0% and 25.0% of the optical thicknessof the underlying antireflective coating 120.

Another general configuration of a stack of thin layers, in connectionwith FIG. 1, is presented in table 4 below, with, for the layers, therecommended materials and also the recommended ranges of thicknesses forthis general configuration.

TABLE 4 Thicknesses Layer No. Coating Material (nm) 168 160 SiN 5.0-15.0 162 ZnO 3.0-8.0 150 NiCr  0-1.0 140 Ag  9.0-16.0 128 120 ZnO3.0-8.0 126 SiZrN 10.0-30.0 124 SiZrN′   0-15.0 122 SiN  5.0-15.0

In this configuration, only the underlying antireflective coating 120comprises a SiZrN layer 126 based on silicon-zirconium nitride enrichedin Zr; the overlying antireflective coating 160 does not comprise alayer based on silicon-zirconium nitride enriched in Zr.

In this case, the layer based on silicon-zirconium nitride enriched inZr, Si_(x)Zr_(y)N_(z), can be the sole high-index layer of theunderlying antireflective coating 120; its optical thickness can thenrepresent between 30.0% (for y/(x+y) close to 25.0%) and 60.0% (fory/(x+y) close to 40.0%) of the optical thickness of the underlyingantireflective coating 120.

However, it is possible for the underlying antireflective coating 120 tocomprise several high-index layers; in this case, the optical thicknessof the layer based on silicon-zirconium nitride enriched in Zr,Si_(x)Zr_(y)N_(z), can then represent between 15.0% (for y/(x+y) closeto 25.0%) and 30.0% (for y/(x+y) close to 40.0%) of the opticalthickness of the underlying antireflective coating 120; it then beingpossible for the optical thickness of the other high-index layer (suchas, for example, a layer made of SiZrN′, based on conventionalsilicon-zirconium nitride) or the sum of the optical thicknesses of theother high-index layers, in the case where there are several of them, torespectively represent between 15.0% and 30.0% of the optical thicknessof the underlying antireflective coating 120.

For all the examples below, the conditions for deposition of the layersare:

TABLE 5 Deposition Layer Target employed pressure Gas SiN Si:Al at 92:8wt % 1.5 × 10⁻³ mbar Ar/(Ar + N₂) at 55% ZnO Zn:O at 50:50 atom % 2 ×10⁻³ mbar Ar/(Ar + O₂) at 90% NiCr Ni:Cr at 80:20 atom % 8 × 10⁻³ mbarAr at 100% SiZrN′ Si:Zr:Al at 78:17:5 atom % 2 × 10⁻³ mbar Ar/(Ar + N₂)at 45% SiZrN Si:Zr:Al at 68:27:5 atom % 2 × 10⁻³ mbar Ar/(Ar + N₂) at45% or at 58:37:5 atom % SiZrN″ Si:Zr:Al at 48:47:5 atom % 2 × 10⁻³ mbarAr/(Ar + N₂) at 45% TiO TiO₂ 2 × 10⁻³ mbar Ar/(Ar + O₂) at 95% TiZrOTiZrO₄ 2 × 10⁻³ mbar Ar/(Ar + O₂) at 95% SnZnO Zn:Sn at 64:36 atom % 2 ×10⁻³ mbar Ar/(Ar + O₂) at 50% SiO₂ Si:Al at 92:8 wt % 2 × 10⁻³ mbarAr/(Ar + O₂) at 50% Ag Ag 8 × 10⁻³ mbar Ar at 100%

In all the examples below, the stack of thin layers is deposited on asubstrate made of clear soda-lime glass with a thickness of 4 mm of thePlaniclear brand, distributed by Saint-Gobain.

The physical thicknesses in nanometers of each of the layers or of thecoatings of the examples are set out in tables 6, 8, 10 and 11 below andthe main data relating to examples 1 to 10 are combined in table 3.

In tables 6, 8, 10 and 11, the “No.” column indicates the number of thelayer and the second column indicates the coating, in connection withthe configuration of FIG. 1; the third column indicates the materialdeposited for the layer of the first column, with, for the layers madeof “SiZrN”, “SiZrN′” and “SiZrN”, a value in brackets which denotes, forthis layer of this example, the Zr/(Zr+Si+Al) atomic ratio, as apercentage.

In tables 7, 9 and 12, the characteristics of the substrate coated witha stack which are presented consist, for each of these examples, after atempering heat treatment of the coated substrate at 650° C. for 10minutes, followed by cooling, using the illuminant D65 2° for examples 1to 5 and the illuminant D65 10° for examples 6 to 18, of themeasurement:

-   -   for LT, of the luminous transmission in the visible region, in        %,    -   for Ta* and Tb*, of the colors in transmission in the La*b*        system,    -   for LRs, of the luminous reflection in the visible region, in %,        stack side,    -   for Rsa* and Rsb*, of the colors in reflection in the La*b*        system, stack side,    -   for LRg, of the luminous reflection in the visible region, in %,        glass side,    -   for Rga* and Rgb*, of the colors in reflection in the La*b*        system, glass side, and    -   for E, of the emissivity.

For examples 1 to 5, “g” indicates the measurement of the solar factorin a double glazing configuration, consisting of an external substratemade of clear 4-mm glass, of an inserted 16-mm space filled with argonand of an internal substrate made of clear 4-mm glass, with the stacklocated on face 3, that is to say on the face of the internal substratefacing the inserted space.

For examples 6 to 18, “g” indicates the measurement of the solar factorin a triple glazing configuration, consisting of an external substratemade of clear 4-mm glass, of an inserted 12-mm space filled with argon,of a central substrate made of clear 4-mm glass, of an inserted 12-mmspace filled with argon and of an internal substrate made of clear 4-mmglass, with the stack located on face 2 and 5, that is to say on theface of the external substrate and of the internal substrate which isfacing the inserted space.

TABLE 6 Ex. No. 1 2 3 4 5 168 160 SiN 42.0 28.7 30.3 32.3 36.0 166 SiZrN— —  9.0 (27%)  6.7 (37%) — 164 SiZrN′ — 11.8 (17%) — — 3.8 (47%) orSiZrN″ 162 ZnO 5.0 5.0 5.0 5.0 5.0 150 NiCr 1.0 1.0 1.0 1.0 1.0 140 Ag15.0 15.0 15.0 15.0 15.0 128 120 ZnO 5.0 5.0 5.0 5.0 5.0 126 SiZrN — —17.5 (27%) 13.7 (37%) — 124 SiZrN′ — 20.8 (17%) — — 8.7 (47%) or SiZrN″122 SiN 28.6 5.0 5.0 9.0 15.3

TABLE 7 Ex. 1 2 3 4 5 LT 78.3 80.9 72.4 82.8 81.9 Ta* −1.3 −1.2 −1.3−1.5 −1.5 Tb* 5.1 4.6 4.9 5.2 5.7 LRs 13.3 10.6 8.4 7.8 8.3 Rsa* 2.9 2.62.4 2.2 2.3 Rsb* −14.8 −14.2 −12.1 −10.2 −9.5 LRg 16.2 13.3 11.1 10.511.2 Rga* 1.4 0.7 −0.5 −0.9 −1.0 Rgb* −12.5 −11.2 −8.0 −6.2 −5.8 E (%)2.2 2.2 2.2 2.2 2.2 g (%) 55.4 57.1 58.5 58.8 58.8

In the first series of examples, that of tables 6 and 7, example 1constitutes a base example of the technology of silver monolayer low-estacks comprising barrier layers, as disclosed in the patent applicationEP 718 250: the functional layer 140 made of silver is depositeddirectly on a wetting layer 128 made of zinc oxide and an overblockerlayer 150 made of NiCr is provided immediately over this functionallayer 140, followed by another layer 162 made of zinc oxide. Thisassembly is framed by a lower barrier layer 122, based on siliconnitride, and an upper barrier layer 168, also based on silicon nitride.

This example 1 exhibits a high luminous transmission LT, of the order of78%, and a low emissivity E, of the order of 2%; its solar factor, g, asdouble glazing, is moderate, of the order of 55%, and some colorimetricdata are satisfactory in the sense that, in particular, Tb* is close to5.0, which implies a color in transmission which is not too yellow; onthe other hand, one colorimetric datum is not satisfactory: Rsa* is toohigh, which implies a color in reflection on the stack side which is toored.

Example 2 constitutes an improvement in the base technology of example 1as the luminous transmission LT is increased, which results in anincrease in the solar factor in the same double glazing configuration.Of course, the emissivity is retained since the functional layerexhibits the same thickness and is framed directly by the same layers.Tb* is close to 5.0, which is satisfactory, and Rsa* is close to 2.5,which is also satisfactory.

This is obtained because, on the one hand, a portion of the lowerbarrier layer 122 is replaced with a high-index and barrier layer 124and, on the other hand, a portion of the upper barrier layer 168 isreplaced with a high-index and barrier layer 164.

This example 2 is capable of improvement in the sense that, if theluminous transmission were to be very high, of the order of 82% or more,then the solar factor might be even higher.

Example 3 constitutes an improvement owing to the fact that the veryhigh luminous transmission makes it possible to achieve a high solarfactor, of greater than 58%. The emissivity is, of course, retained andthe colorimetric data are satisfactory as Tb* is close to 5.0 and Rsa*is close to 2.5.

Example 4 also constitutes an improvement owing to the fact that thevery high luminous transmission, even higher than that of example 3,makes it possible to achieve a solar factor close to 59%. The emissivityis, of course, retained and the colorimetric data are satisfactory asTb* is close to 5.0 and Rsa* is close to 2.5.

Example 5 does not constitute an improvement with respect to example 4as it exhibits a lower luminous transmission and a lower solar factor.

Example 5 does not constitute an improvement with respect to example 2because, even though it exhibits a very high luminous transmission andmakes it possible to achieve a high solar factor, Tb* is too far from5.0.

In a second series of examples, the reference example, No. 6, is chosento be similar to example 1 of the first series, with the same layersequence, but with a thinner functional layer than for the first series.

TABLE 8 Ex. No. 6 7 8 9 10 168 160 Si₃N₄ 35.0 37.0 38.8 38.8 38.0 162ZnO 5.0 5.0 5.0 5.0 5.0 150 NiCr 1.0 1.0 1.0 1.0 1.0 140 Ag 9.8 9.8 9.89.8 9.8 128 120 ZnO 5.0 5.0 5.0 5.0 5.0 126 SiZrN — — 19.4 (27%) 13.6(37%) — 124 SiZrN′ — 29.2 (17%) — — 8.7 (47%) or SiZrN″ 122 Si₃N₄ 34.45.4 16.0 24.4 31.1

TABLE 9 Ex. 6 7 8 9 10 LT 88.6 89.2 88.9 88.9 88.7 Ta* −0.9 −1.0 −1.1−1.3 −1.2 Tb* 2.0 1.6 2.2 2.5 2.8 LRs 4.7 4.5 4.6 4.6 4.5 Rsa* 2.6 2.12.0 1.9 1.9 Rsb* −12.0 7.8 −6.5 −6.2 −6.0 LRg 5.9 5.3 5.5 5.4 5.4 Rga*1.7 0.9 −0.5 −0.5 −0.3 Rgb* −12.9 −8.2 −5.0 −5.1 −6.1 E (%) 4.2 4.2 4.24.2 4.2 g (%) 55.8 57.1 57.5 57.4 57.2

In the second series of examples, that of tables 8 and 9, example 6exhibits a high luminous transmission LT and a low emissivity E; thesolar factor, g, as triple glazing with two stacks according to theexample, one on face 2 and the other on face 5, is moderate, of theorder of 55%, and some colorimetric data are satisfactory in the sensethat, in particular, Tb* is close to 2.0, which implies a color intransmission which is not too yellow; on the other hand, onecolorimetric datum is not satisfactory: Rsa* is too high, which impliesa color in reflection on the stack side which is too red.

Example 7 constitutes an improvement in the technology of example 6 asthe luminous transmission LT is increased, which results in an increasein the solar factor in the same triple glazing configuration. Of course,the emissivity is retained since the functional layer exhibits the samethickness and is framed directly by the same layers. Tb* decreases,which is satisfactory, and Rsa* is close to 2.0, which is alsosatisfactory.

This is obtained owing to the fact that a portion of the lower barrierlayer 122 is replaced with a high-index and barrier layer 124.

This example 7 is capable of improvement in the sense that the solarfactor might be even higher.

Example 8 constitutes an improvement owing to the fact that the luminoustransmission is higher than that of example 6; it is not as high as thatof example 7 but makes it possible to achieve a greater solar factorthan that of example 7. The emissivity is, of course, retained and thecolorimetric data are satisfactory as Tb* is close to 2.0 and Rsa* isclose to 2.0.

Example 9 also constitutes an improvement with respect to examples 6 and7 owing to the fact that the luminous transmission is as high as that ofexample 8 and that the solar factor is as high as that of example 8. Theemissivity is, of course, retained and the colorimetric data aresatisfactory as Tb* is close to 2.0, even if it has moved away from itin comparison with example 8, and Rsa* is close to 2.0.

Example 10 does not constitute an improvement with respect to example 9as it exhibits a lower luminous transmission and a lower solar factor.

Example 10 does not constitute an improvement with respect to example 7because, even though it exhibits a high luminous transmission, Tb* istoo far away from the value of 2.0 obtained with example 6.

TABLE 10 Ex. No. 3 11 12 13 14 168 160 SiN 30.3 30.3 30.0 30.0 18.0 166SiZrN  9.0 (27%) — — — — 164 SiZrN″ — 9.0 (47%) — — — TiO_(x) — — 9.0 —— TiZrO_(x) — — — 9.0 — 163 SnZnO — — — — 22.0 162 ZnO 5.0 5.0 5.0 5.05.0 150 NiCr 1.0 1.0 1.0 1.0 — 140 Ag 15.0 15.0 15.0 15.0 15.0 128 120ZnO 5.0 5.0 5.0 5.0 5.0 126 SiZrN 17.5 (27%) — — — — 124 TiO_(x) — 18.018.0 — — TiZrO_(x) — — — 18.0 19.0 123 SnZnO — — — — 10.0 122 SiN 5.015.3 15.3 15.3 —

In the third series of examples, that of table 10, the preceding example3 is taken as reference and examples 11 to 14 have been designed inorder to obtain the same optical properties after heat treatment as thisexample 3; this is the reason why these data are not shown.

Example 14 is an example based on the teaching of international patentapplication No. WO 2014/191472.

Examples 11 to 14 do not withstand the heat treatment of 650° C. for 10minutes: example 11 exhibits numerous large defects, with star-shapedblemishes with a width of the order of 0.5 micron; example 12 exhibits avery significant haze and a great many fine defects, of the order of 0.1micron; examples 13 and 14 do not exhibit a haze but a great many finedefects, of the order of 0.1 micron; only example 3 is devoid of largedefects, of fine defects and of haze.

TABLE 11 Ex. No. 7 15 16 17 18 169 160 SiO — 30.0 30.0 30.0 30.0 168Si₃N₄ 37.0 26.4 27.1 13.1 13.0 166 SiZrN — — — — 13.0 (27%) 164 SiZrN′ —— — 13.0 (17%) — 162 ZnO 5.0 5.0 5.0 5.0 5.0 150 NiCr 1.0 1.0 1.0 1.01.0 140 Ag 9.8 9.8 9.8 9.8 9.8 128 120 ZnO 5.0 5.0 5.0 5.0 5.0 126 SiZrN— — 19.1 (27%) — 21.1 (27%) 124 SiZrN′ 29.2 (17%) 19.6 (17%) — 21.5(17%) — 122 Si₃N₄ 5.4 15.5 14.0 16.4 15.0

TABLE 12 Ex. 7 15 16 17 18 LT 89.2 88.8 89.2 89.0 89.3 Ta* −1.0 −1.2−1.4 −1.4 −1.8 Tb* 1.6 1.7 1.9 2.4 2.7 LRs 4.5 4.6 4.4 4.7 4.7 Rsa* 2.12.1 2.0 2.0 2.0 Rsb* 7.8 −8.3 −7.1 −9.4 −6.8 LRg 5.3 5.9 5.5 5.9 5.7Rga* 0.9 0.7 0.4 1.2 1.0 Rgb* −8.2 −6.5 −4.4 −8.7 −6.6 E (%) 4.2 4.2 4.24.2 4.2 g (%) 57.1 57.4 58.1 57.9 58.7

In the fourth series of examples, that of tables 11 and 12, thepreceding example 7 is taken as reference. Examples 15 and 17 eachcorrespond to an improvement in this example 7 with the insertion, intothe dielectric coating overlying the functional layer 140, of a layermade of dielectric material of low index, the layer 169, made of SiO. Inaddition, for example 17, the dielectric coating overlying thefunctional layer 140 comprises a layer made of dielectric material ofhigh index, the layer 164, made of SiZrN′, that is to say made ofconventional silicon-zirconium nitride.

The layer 169 contributes to a higher solar factor being obtained; asseen in table 12, example 15 exhibits a solar factor, g, increased by0.3% in triple glazing configuration as explained above, with respect tothat of example 7, and example 17 exhibits a solar factor, g, increasedby 0.8% in triple glazing configuration as explained above, with respectto that of example 7.

Example 16 constitutes an example according to the invention and animprovement in example 15: the replacement of the dielectric material ofthe layer of high index, the layer 126, made of SiZrN′, with adielectric material layer of higher index, the layer 128, made of SiZrN,that is to say made of silicon-zirconium nitride enriched in Zr, makesit possible to further increase the solar factor, by 0.7% with respectto that of example 15, in the same triple glazing configuration, byvirtue of obtaining a very high luminous transmission, which is found tobe that of example 7.

Example 18 constitutes an example according to the invention and animprovement in example 17: the replacement of the dielectric materiallayer of high index, the layer 164, made of SiZrN′, with a dielectricmaterial layer of higher index, the layer 166, made of SiZrN, that is tosay made of silicon-zirconium nitride enriched in Zr, makes it possibleto further increase the solar factor, by 0.8% with respect to that ofexample 17, in the same triple glazing configuration, by virtue ofobtaining a very high luminous transmission.

Examples 15 to 18 have been configured with a low-index dielectriclayer, the layer 169, which exhibits a thickness of 30 nm; thisthickness constitutes a favorable choice between the desired effect ofimproving the solar factor and the ease of deposition of this layer.Other solutions are acceptable with a thickness of this low-indexdielectric layer of between 15.0 and 60.0 nm. The choice of a thicknessof this low-index dielectric layer of 55.0 nm results, for example, inthe solar factor being further increased by 0.3%.

Furthermore, tables 7, 9 and 12 show that the examples exhibit opticalcharacteristics which are acceptable from the viewpoint of expectationsand in particular a low coloration, both in transmission and inreflection, on the stack side or on the glass side, and also a lowluminous reflection in the visible region, both on the stack side LRsand on the glass side LRg.

Tests have furthermore been carried out with targets of 68.0 atom % to66.0 atom % of Si per 27.0 atom % to 29.0 atom % of Zr with 5 atom % ofAl in all cases, which corresponds to a range of atomic ratio of Zr tothe sum Al+Si+Zr, y/(w+x+y), between 27.0% and 29.0%, these values beingincorporated; these targets being sputtered in a nitrogen-containingatmosphere.

These tests have made it possible to obtain layers with refractiveindices at 550 nm between 2.37 and 2.42, these values beingincorporated, which is particularly favorable.

As a result of the low sheet resistance obtained and also of the goodoptical properties (in particular the luminous transmission in thevisible region), it is furthermore possible to use the substrate coatedwith the stack according to the invention to produce a transparentelectrode substrate.

Generally, the transparent electrode substrate may be suitable for aheated glazing, for an electrochromic glazing, for a display screen, oralso for a photovoltaic cell (or panel) and in particular for atransparent photovoltaic cell backsheet.

The present invention is described in the preceding text by way ofexample. It is understood that a person skilled in the art is able toproduce different alternative forms of the invention without, however,departing from the scope of the patent as defined by the claims.

1. A transparent substrate comprising, on a main face, a stack of thinlayers comprising a single metallic functional layer having propertiesof reflection in the infrared region and/or in the solar radiationregion, and two antireflective coatings, said antireflective coatingseach comprising at least one dielectric layer, said functional layerbeing positioned between the two antireflective coatings, wherein atleast the antireflective coating located between said substrate and saidfunctional layer comprise(s) a layer comprising silicon-zirconiumnitride, Si_(x)Zr_(y)N_(z), with an atomic ratio of Zr to the sum Si+Zr,y/(x+y), which is between 25.0% and 40.0%, these values beingincorporated.
 2. The substrate as claimed in claim 1, wherein said layercomprising silicon-zirconium nitride, Si_(x)Zr_(y)N_(z), exhibits anitridation z of between 4/3(x+y) and 5/3(x+y), these values beingincorporated.
 3. The substrate as claimed in claim 1, wherein said layercomprising silicon-zirconium nitride, Si_(x)Zr_(y)N_(z), does notcomprise oxygen.
 4. The substrate as claimed in claim 1, wherein theantireflective coating located between said substrate additionallycomprises a layer comprising zirconium-free silicon nitride.
 5. Thesubstrate as claimed in claim 4, wherein said layer comprisingzirconium-free silicon nitride exhibits a thickness of between 5.0 and25.0 nm, these values being included.
 6. The substrate as claimed inclaim 1, wherein the antireflective coating located above saidfunctional layer on the opposite side from said substrate additionallycomprises a layer comprising zirconium-free silicon nitride.
 7. Thesubstrate as claimed in claim 6, wherein said layer comprisingzirconium-free silicon nitride exhibits a thickness of between 25.0 and35.0 nm, these values being included.
 8. The substrate as claimed inclaim 1, wherein the antireflective coating located above saidfunctional layer and on the opposite side from said substrateadditionally comprises a layer made of a dielectric material having alow index.
 9. The substrate as claimed in claim 1, wherein a layer basedon zinc oxide is located below and in contact with said functionallayer.
 10. The substrate as claimed in claim 1, wherein said layercomprising silicon-zirconium nitride, Si_(x)Zr_(y)N_(z), which islocated between said substrate and said functional layer, exhibits athickness of between 10.0 and 30.0 nm, these values being included. 11.The substrate as claimed in claim 1, wherein said layer comprisingsilicon-zirconium nitride, Si_(x)Zr_(y)N₇, which is located above saidfunctional layer on the opposite side from said substrate 44 exhibits athickness of between 6.0 and 12.0 nm, these values being included.
 12. Aglazing comprising at least one substrate as claimed in claim
 1. 13. Theglazing as claimed in claim 12, mounted as a monolithic unit or as amultiple glazing unit of the double glazing or triple glazing orlaminated glazing type, wherein at least the substrate carrying thestack is bent and/or tempered.
 14. The substrate as claimed in claim 1,wherein the substrate is produced in a transparent electrode of a heatedglazing or of an electrochromic glazing or of a lighting device or of adisplay device or of a photovoltaic panel.
 15. A process for themanufacture of the substrate as claimed in claim 1, comprisingmanufacturing said layer comprising silicon-zirconium nitride,Si_(x)Zr_(y)N₇, by sputtering, in a nitrogen-comprising atmosphere, atarget comprising an atomic ratio of Zr to the sum Si+Zr, y/(x+y), whichis between 25.0% and 40.0%, these values being incorporated.
 16. Theprocess as claimed in claim 15, wherein said atmosphere does notcomprise oxygen.
 17. A target for the implementation of the process asclaimed in claim 15, comprising an atomic ratio of Zr to the sum Si+Zr,y/(x+y), which is between 25.0% and 40.0%, these values beingincorporated.
 18. The substrate as claimed in claim 1, wherein thesingle metallic functional layer having properties of reflection in theinfrared region and/or in the solar radiation region is based on silveror on silver-containing metal alloy.
 19. The substrate as claimed inclaim 1, wherein both of the antireflective coatings comprise the layercomprising silicon-zirconium nitride, Si_(x)Zr_(y)N_(z), with an atomicratio of Zr to the sum Si+Zr, y/(x+y), which is between 25.0% and 40.0%,these values being incorporated
 20. The substrate as claimed in claim 1,wherein the atomic ratio of Zr to the sum Si+Zr, y/(x+y), is between27.0% and 37.0%, these values being incorporated